One of the things Eco Brooklyn is focused on is eliminating the use of concrete.  Concrete is normally used in the following areas of the brownstone:

the foundation footings, the cellar floor, front sidewalk.

Concrete and its ingredient of cement is not green. It produces massive amounts of CO2. So we are eager to find alternatives.

For the cellar floor we are experimenting with earthen floors with great success. An earthen floor is still a very hard material. It can withstand the pointy feet of heavy furniture, it isn’t much bothered by heavy things dragged along it and it looks great.

For the sidewalk we like salvaged bluestone pavers.

For foundation footings we haven’t found a replacement. If you are underpinning the foundation you have inevitably dug the cellar floor down, which means you have lots of salvaged stone. We pack the footings with stone and only use the concrete as binder in the cracks. This reduces the amount we need considerably.

Recently however I have discovered the work of the Geopolymer Institure. Their claim to fame is they discovered that the Pyramids were not built entirely out of carved limestone blocks. Many of those blocks are actually poured in place limestone cement!

Here is a video showing the process:

This has really gotten my head spinning. What if we could use the same technique to make cement for Brooklyn brownstones! That would be a great step forward in removing a major environmental polluter.

This page is also chock full of information about the process.

Here is a more in depth talk about this cement: